[swift-evolution] Proposal: Tuple Convertible

[Tal Atlas]

Overall this is an interesting idea but in practice I think what you’re
looking for is more of scala implicit conversions. A way to define a
conversion from one type to another so that when you cast the implicit
conversion gets run for you. It’s much more flexible and gives you what you
want without only working for tuples.

On Mon, Dec 7, 2015 at 1:02 AM John McCall via swift-evolution <
swift-evolution at swift.org> wrote:

> On Dec 6, 2015, at 4:07 PM, Nikolai Vazquez via swift-evolution <
> swift-evolution at swift.org> wrote:
>
> I was thinking it could work for variables that are already tuples but
> then that goes against Swift's strict typing. So really it should only be
> for tuple literals.
>
>
> I think this is an interesting idea, but I believe it’s not actually
> expressible in the current generics system without hard-coding the protocol
> to just 2-tuples.
>
> John.
>
>
> On Sun, Dec 6, 2015, 7:01 PM Stephen Celis <stephen.celis at gmail.com>
> wrote:
>
>> Do you mean a TupleLiteralConvertible? I’m also in favor of a
>> ClosureLiteralConvertible (or FunctionLiteralConvertible).
>>
>> Stephen
>>
>> On Dec 6, 2015, at 6:40 PM, Nikolai Vazquez via swift-evolution <
>> swift-evolution at swift.org> wrote:
>>
>> When working with points, I’ll sometimes make a typealias to an integer
>> tuple:
>>
>> typealias Point = (x: Int, y: Int)
>>
>> However, if I want to add extended functionality to my Point type, I
>> would have to change it to a struct, removing the ability to create one
>> on the fly with a tuple.
>>
>> I’m proposing a TupleConvertible protocol that allows initialization
>> from a tuple directly.
>>
>> struct Point: TupleConvertible {
>>
>>     var x, y: Int
>>
>>     init(x: Int, y: Int) {
>>         self.x = x
>>         self.y = y
>>     }
>>
>>     init(tuple: (x: Int, y: Int)) {
>>         self.init(x: tuple.x, y: tuple.y)
>>     }
>>
>> }
>>
>> This would make it very easy to create new Point instances.
>>
>> let somePoint: Point = (50, 120)let otherPoint = Point(x: 50, y: 120)
>>
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